# NTSB SEA01LA128: Tibert Baby Lakes, N94AT, Stevensville, MT, July 7, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 7, 2001, 10:20 local (16:20 UTC) - Place: Stevensville, MT - Coordinates: 46.499221, -114.100868 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.4992&lon=-114.1009&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2001 - Report: Approved by Office Director - Parties: Helena FSDO - NTSB case key (mKey): 52675 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA01LA128 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52675/pdf - Page: https://openairdocs.org/ntsb/SEA01LA128 ## Probable cause The pilot's failure to maintain directional control of the tailwheel-equipped aircraft during the landing roll. Factors include the pilot's low total time in this make and model aircraft and his lack of recent experience in this make and model aircraft. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, landing - roll - directional control - not maintained, pilot in command (cause) - lack of recent experience in type of aircraft (contributing factor) - lack of total experience in type of aircraft (contributing factor) - Gear collapsed, landing - roll - landing gear,main gear - overload ## Analysis The pilot, who had accumulated approximately three hours flight time in this make and model aircraft prior to the accident flight, had not flown the airplane in about 18 months. He flew it around the area for about one hour getting reacquainted with its characteristics, and then attempted a full-stop landing. Although the touchdown was uneventful, during the landing roll, the aircraft started drifting to the left. The pilot therefore applied right rudder, but over-corrected. Before he could get the aircraft realigned with the runway, the left main gear collapsed, and the left lower wing impacted the runway surface. ## Factual narrative On July 7, 2001, approximately 1020 mountain daylight time, a tailwheel-equipped experimental Tibert Baby Lakes biplane, N94AT, experienced a ground loop during the landing roll at Stevensville Airport, Stevensville, Montana. The private pilot, who was the sole occupant, was not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed the same location about one hour earlier, was being operated in visual meteorological conditions. No flight plan had been filed. There was no report of an ELT activation. According to the pilot, who had accumulated about three hours total time in this make and model aircraft prior to this flight, it had been about 18 months since he had last flown the aircraft. After takeoff, he flew around the area for about an hour performing maneuvers that would reacquaint him with the aircraft's characteristics. He then returned to the airport for landing. During the landing attempt, the touchdown was uneventful, but the aircraft started drifting to the left during the landing roll. Therefore, the pilot applied right rudder to correct the left drift, but "over-corrected." Before he was able to bring the aircraft back into alignment with the runway, "...the side-load on the left gear caused it to collapse." Immediately after the collapse of the gear, the lower left wing impacted the surface of the runway. According to the pilot, it was a calm, clear day. ## Aircraft - Registration: [N94AT](https://openairdocs.org/deregistered/N94AT-2024-05-04), registration cancelled 2024-05-04, S/N 82963BGL, built 1994 (OpenAirDocs) - Reported make and model: Tibert Baby Lakes - Registry model: [Tibert Andrew E BABY GREAT LAKES](https://openairdocs.org/model/tibert-andrew-e-baby-great-lakes) (registry code 05624S6) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 82963BGL - Airframe hours: 31 - Engines: Lycoming O-235-C1 115 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: James F. Johnson - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, June 14, 2001, 2 hours before - Departed: 32S, Stevensville, MT - Airport: 32S, Stevensville Airport, runway 12, 3,800 × 60 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review May 25, 2000; seat: front; flight hours: 1,618 total, 4 in this make and model, 12 in the last 90 days, 6 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 61 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20010707018059A](https://openairdocs.org/incident/20010707018059A), Jul 7, 2001: Stevensville, MT, No damage. (-23) Pilot stated he over corrected from a swerve to the left. Left gear collapsed after ground loop. ## Other investigations on N94AT (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB SEA96LA096](https://openairdocs.org/ntsb/SEA96LA096), May 20, 1996: Tilbert Baby Great Lakes (N94AT), Stevensville, MT, substantial damage. Probable cause: the pilot's inadequate compensation for the wind conditions during the landing roll, which resulted in loss of directional control and an inadvertent ground swerve. Factors relating to the accident… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.